Electric-arc lamp.



No. 63|,3l3-. Patented Aug. 22, I899.

F. MACKINTOSl-l.

ELECTRIC ABC LAMP.

(Application filed July 16, 1897.)

(No Model.)

UNlTED STATES PATENT OFFICE.

FREDERICK MAOKINTOSH, OF SOHENEOTADY, NEW YORK, ASSIGNOR TO THE GENERALELECTRIC COMPANY, OF NEIV YORK;

ELEGTRlC-ARC LAM P-.

SPECIFICATION formingart Of Letters Patent No. 631,313, dated August 22,1899.

Application filed July 16, 1897. Serial No. 644,859; (No model.)

To cLZZ whom it may concern-.-

Be it known that I, FREDERICK MAOKIN- TOSH, a citizen of the UnitedStates, residing at Schenectady, in the county'of Schenectady, State ofNew York, have invented certain new and useful Improvements inElectric-Arc Lamps, (Case No. 531,) of which the following is aspecification.

The present invention has for its object to provide a suitable feedmechanism with a simple and inexpensive reflector of such a characterthat the light reflected thereby shall be soft and evenly diifused andsuitable for engraving and photographing.

In the accompanying drawings, attached to and made a part of thisspecification, Figure 1 is a side elevation of my improved lamp. Fig. 2is a front elevation with the base broken away. Figs. '3 and 4 arerespectively a longitudinal and cross section through the reflector, andFig. 5 is a partial view showing the preferred position of the carbonswith respect to the reflector.

Mounted upon a suitable base or stand A is a fork-shaped standard B,supporting at its upper end the reflector C and lamp mechanism. Thestandard is secured to the base by a bolt D, with a spring-washer Einterposed between the head and the standard, permitting the parts to bemoved with respect to each other, for training the beam of light in thehorizontal plane, and at the same time preventing accidental movement.Pivotally secured in the standard is a yoke F, which supports thereflector O and the lamp mechanism. One side of the yoke is pivoted tothe standard by a pin F, which is held in place by a cotter, and theother side by a screw-threaded pin F having a clam ping-nut F Extendingrearwardly from the yokeis a handle G, which is employed in directingthe beam of light from the arc, the arrangement of parts being such thatthe beam can be trained over side ranges both vertically andhorizontally.

The lamp mechanism comprises two parallel rods H and I, the latter beingprovided with right and left hand screw-threads arranged in such mannerthat the carbon-holder carriages J and J can be fed toward and away fromeach other by the handle K. The carbon-holders secured to carriages J Jmay be of any desired construction which will permit the carbons to beadjusted therein. As herein shown, the carbons are placed at an angle tothe center line of the reflector, the arrangement being such that therays of light from the crater in the upper carbon will issue in a freeand unobstructed manner.

The reflector 0 com prisesacylindrical casting 0', open at one end andclosed at the other by a parabolic end having a boss 0 thereon, by whichit is secured to the yoke F. Mounted within the casting is a parabolicreflector of porcelain or other refractory material 0 adapted to berendered incandescent by the arc formed between the carbons. Thematerial when heated to this point constitutes a very excellent redoctor and one which intensifies the light to a remarkable degree.Between the reflector and the casting is provided a layer of asbestos,permitting a slight expansion of the reflector independent of thecasting. To secure the reflector in place, a projection O is providedthereon, which engages with a slot in the casting O. In addition to thisa ring L is employed, situated directly in front of the reflector andsecured to the casting-by screws. Surrounding the outer end of thecastiug'aud secured thereto is a hood M, adapted'to serve as a supportfor a plate of colored glass or a lantern-slide. 7 Two holes N and'N,extending into the interior of the reflector, are provided, throughwhich the upper and lower carbons extend. These holes are somewhatlarger than the carbons, so as to prevent the are from being short cir-'cuited through the outer casting.

In Fig. 5 is shown a slight modification of my invention, in which thecarbons are placed at right angles to the center line of their reflectorand the position of holes N and N changed. I have found that when thecarbons'and reflector are arranged as shown the reflected light is moreevenly diffused than when the carbons are placed as shown in Fig. 1. Inthe latter case when the lightis thrown on a screen or printing-frame itwill be found to be very intense in the center and gradually decrease inintensity toward the outer edge of the beam. With the arrangement shownin Fig. 5 the light from the arc is thrown upon the reflector in suchmanner that it is very evenly diffused, and when employed forblue-printing (a very common use) the result shows an even color on theprint, indicating an even distribution of light from the arc.

Between the casting C and the parabolic reflector is a space I, whichallows for the expansion of the reflector.

In operating the lamp the beam of light is trained both in thehorizontal and vertical direction by the handle G, and as the carbonsare consumed they are given the proper relative feed by the hand-wheelK.

\Vhat I claim as new, and desire to secure by Letters Patent of theUnited States, is

1. An electric-arc lamp having the arc inclosed in a chamber ofrefractory material whose spectrum is rich in chemical rays, a casingfor said material, and an expansionspace between the two filled with arefractory yielding heat-non-conducting material, such as asbestos.

2. An electric-arc lamp having the arc inclosed in a chamber ofrefractory material adapted to be rendered incandescent by the are andwhose spectrum is rich in chemical rays, a casing around said material,a space between the two filled with a yielding refractory heat nonconducting material, and means at the end of the chamber for fasteningthe casing and lining together.

3. An electric-arc lamp comprising an arcinclosure, constituted of anouter casing of iron closed at one end and open at the other, a liningof refractory material whose spectrum is rich in chemical rays, a spacebetween the two filled with a yielding heat-refractory material, meansat the open end of a casing for fastening the lining and easingtogether, and arc-electrodes fed through openings in the side of thecasing.

4c. In an electric-arc lamp, the combination of a base, a fork-shapedstandard mounted on the base for oscillating or rotary movement, a yokepivotally secured to the arms of the fork, a reflector secured to theyoke, lamp mechanism also secured to the yoke, and a handle fordirecting the beam of light.

5. In an electric-arc lamp, the combination of a base, a fork-shapedstandard mounted on the base, a yoke pivotally supported by the fork, ahand-nut for clamping the yoke to the fork, a parabolic reflectorcomposed of refractory material, a casing surrounding the reflector andsecured to the yoke, and a hood secured to the casingforsupporting alanternslide or plate of glass.

In witness whereof I have hereunto set my hand this th day of June,1897.

FREDERICK MACKINTOSII.

Witnesses:

B. B. HULL, A. F. MACDONALD.

